Hydraulic shock absorber



Jan. 3, 1933., F Q, KILGR 3,59935953 HYDRAULIC sHocK ABSORBER Filed Nov 7, 1929l Patented Jan. 3, 1933 STATES HYDRAULIC SHOCK ABSORCBER Application filed November 7, 1929. Serial No. 405,373.

This invention relates to a cushioning device or shock absorber for motor vehicles, and of that type in which oil or other fluids are employed to resist movement of a piston operatively connected with a spring which supports the body of the motor vehicle.

One object of the invention is to provide a novel shock absorber ol. this type in which provision is made for adjusting a resistance 1.0 offered by the luid to the movement of the piston in opposite directions in a novel and superior manner.

A further object of the present invention is to provide a novel and improved construcl-5 tion of shock absorber of the character specitied in which provision is made for maintaining a lubricating packing between the operating shaft and its bearing in a novel and superior manner, preventing the usual 20 leakage around the operating shaft which has been experienced in prior types of shock absorbers of this general character.

A still further object lof the invention is to provide a novel and simplilied construction ,of shock absorber of this type which may be manufactured more economically than prior constructions oli-which I am aware, .and which is substantial in construction and durable in operation.

These and .other Jeatures of this invention Will be `pointed out in the `claims at the end vot this specification.

In the drawing illustrating one ,embodiment of the invention- Fig. 1 represents a portion of a motor vehicle provided with .a shock absorber embodying the invention;

Fig. 2, a front elevation on an enlarged scale of the shock absorber shown in Fig. 1;

Fig. 3, a vertical section talen on the line 3 3, Fig. 2;

Fig. 4, a sectional detail ,on the line 4 4, Fig. V3, illustrating the improved device for n adjusting sthe v.by-pass of the fluid from one chamber to another, and

Fig. 5, a detail in similar section illus- .trating the valve in a dilerent ,position of adjustment.

` The vembodiment of the invention herein 5 shown is especially designed for the use of oil or other luid as the resisting` medium, and is provided with a rock-shaft having a piston or Wing 12 extended radially therefrom near the inner end thereof and located in a casing 13 in which the piston 12 oscillates. 55

The roclcshaft 10 has its inner end jour naled in a circular recess 14 in the rear wall 15 of the casing 13, and has its outer end journaled in a hub 17 of a removable 'front Wall or lcap member 1S for the casing 13. C0

In the present case, the casing 13 is subdivided into two compartments 22, 23 by a wall or partition 24 having a curved intermediate portion 25 of substantially the same radius as the rock-shaft l0 (see Fig.r 4). 55

The partition or wall 24 is provided with a curved flange 26 which is secured by rivets 27 or otherwise to the rear wall l5 of the casing.

The partition or wall 24 constitutes an 70 abutment for oil or other fluid in the compartment 23 to be forced against by the piston l2 which subdivides the compartment 23 into two lchambers 23, 29, which may be automatically supplied with oil from the compartment 22 through a port 30 in the abutment wall 24.

The port 3() is controlled by a valve 32 adapted to be opened yby gravity and rest upon a supporting device or pin 34 and to be 80 closed by the pressure of .the oil created by the reciprocating piston 12.

The casing 13 is attached to the body or `chassis 36 of the motor vehicle by means of bolts 37 extended through the lugs or ears 85 38 on the casing.

In lthe present instance, the rock-shaft 10 is represented as connected with the front axle 40 of the motor vehicle, which is effected -by a crank or arm 41 attached to the 90 front end of the rockeshaft which projects beyond the hub 17 of the cap member 18 for `the casing 13, and by a link 42 and stirrup 43.

In the operation of .the motor vehicle over the highways obstructions are encountered and the body-supporting springs (not shown) have two distinct movements, to wit:

.a compression or downward movement, and

a rebound or upward movement, and these offer resistance to the movement of the piston.

As herein shown such by-passing of the oil is eected through co-operating grooves 45,

46 formed inthe upper portion ofthe piston 12- secured to the rock-shaft 10, and in the curved portion 25 ofthe partition 24 respectively.

The groove y46 is formedV concentrically with the piston 12 and the rock-shaft '10, and

in the present instance, constitutes the main by-pass for the oil or other fluid from one of the operating chambersV to the'other. The size ofthe groove 46 is preferably made sufficient to permit quite line oscillation of the wing or piston 12 and of the roch-shaft 10. The groove is made eccentric to the groove 46 and is preferablyarranged with the greatest depth under a control valve or plunger 47 to be referred to, and so that the depth of the groove gradually diminishes toward each end of the groove.

` Vhen an excessive road shock is encountered and the piston is moved to an extreme position, the resistance offered to the flow of oil, as it is forced through'the by-pass by the piston, is automatically increased.

Furthermore, because of the tapered construction of the groove 45 in both directions from its center,"'variations in the resistance offered tothe flow of oil are Vautonfiatically rendered proportionate to the extent of the road shock, thus producing a most desirable shock absorber and one which permits most efficient and free spring action during the travel of the motor vehicle over relatively smooth roads, while providing for increased restraint or resistance over poor roads.

Provision is also preferably made for adjusting the extent of the resistance offered to the llow of the oil through the by-pass during the movement of the piston back and forth, and as herein shown the valve or plunger member 47 is mounted within a hole drilled in the casingA and in a portion of the partition 24, as illustrated in Figs. 4 and 5. Y

The plunger 47 may be manually or automatically operated'and in the present instance is designed to bemanually operated, and 1s 'provided upon its upper end with a threaded plug 48 which is screwed yinto a threaded portion of the hole to thereby permit the convenient adjustment of the position of the plunger 47 by screwing the plug into and out of its threaded hole.

The plunger 47 is arranged to extend transversely ofand preferably to form a valve for the concentric groove 46, and the into the threaded hole until the plug engages `the bot-tom of the hole, the plunger 47 will extend completely across the groove 46 for its entire depth.

From' the description thus far, and an inl n spection of Figs. 4 and 5, it will be apparent that during the oscillations of the piston 12 bach and forth under normal road conditions, the effective depth of the groove 86 will be adj ustably determined by the position of the plunger v 47. The adjusting plug for the plunger 47 is concealed by a closure plug 49 screwedinto a threaded hole in they casing, and when it is desired to vary the resistance offered to the by-pass of the oil, it isonly necossary to remove the plug 49, and by means of a screw-driver alter the position of theadjusting plug, thus elfectively controlling the depth ofthe groove 46. i l

Provision is preferably made in the present apparatus for minimizing the leakage of the oil or other i'iuid from either of the operating chambers 28, 29 outwardly along the rock-shaft 10, and as hereinshown, an annular groove 50 is-provided, as shown in Fig. 3, in the cap member 18 in a position arranged to catch any oil which may pass from saidoperating chambers and flow along the rockshaft, and a passage 52 formed in the cap member 18 is arranged so that any oil accumulating in the annular groove 50 may be coni by beveling olf the inner end of the casing.

The annular groove 70 is connected with the supply chamber 22 by a slot 71 inthe inner end of the casing at the top thereof as shown in Fig. 3.

The rock-shaft 10 may and 'preferably will be provided with a novel and highly efficient packing for insuring against the leakage of any oil out between the shaft andfits bearing in the front wall or cap member 18, and as herein shown the hub 17 of the cap member 18 is provided with an annular groove 58 with which communicates a hole 60 drilled in a bossv 61 on the said hub. rEhe hole 60 and the annular groove 58 are lled with a plastic packing 59, which may be a mixture of sawdust and graphite, or other suitable materials, and pressure ismaintained upony the body of the packing by means ofv a plunger 64 positioned in the hole 60.

The plunger l64 is urged against the packing to, force. it through the hole 60anol into the annular groove 58 by a spring 66 interposed between the plunger 64 and screw cap 68 which serves not only to close the end of the hole 60, but also to adjustably determine the compression in the spring and consequently to enable a substantially uniform pressure to be exerted on the packing during the life of the shoclrabsorber, thus maintaining a fluid-tightjoint between the rock-shaft and its bearing and avoiding the usual oil leakage which has been experienced with shock absorbers of the oil type, after the same have become slightly worn in use.

From the above description, it will be observed that the flow of oil or other iiuid in opposite directions from one of the chambers 28, 29 to the other, is controlled by an adjustable device carried by a stationary part of the absorber and which is accessible to the operator from outside of the shock absorber, and while it may be preferred to employ the construction herein shown for accomplishing this result, it is not desired to limit the invention to the particular construction shown.

Under relatively smooth or normal road conditions, the piston or Wing 12 is designed to have a limited movement in opposite directions so that the tapered end portions of the eccentric groove 45 are not brought into use Vto materially diminish the flow of fluid from one chamber 2S, 29 to the other, but when the road condition becomes rough or abnormal, the movement of the piston 12 is extended to bring into use vthe tapered ends of the eccentric groove 45 and thereby increase the resistance to the flow of the fluid from one chamber to the other. As a result a gentle and smooth action is provided for the motor vehicle while traveling over normal roads and a gradually increasing resistance at the ends of the movement of the body of the vehicle in opposite directions is provided while the motor vehicle is traveling over rough or abnormal roads.

It may be preferred to use the eccentric groove with the concentric groove as hereinshown, but it is not desired to limit the invention in this respect.

Having thus described the invention, what is Claimed is:

1. In a shock absorber, in combination, a casing, a rock-shaft extended into the casing, a piston secured to the rock-shaft, a partition member extending around the rock-shaft and piston, {luid-containing chambers on opposite sides of the piston, a by-pass between said chambers comprising a groove formed in said partition, a second groove formed in the piston and having tapering portions for automatically restricting the iow of liquid through the by-pass as the travel of the piston is extended under abnormal road conditions, and a device extended into the firstmentioned groove for restricting the flow of fluid therethrough.

2. In a shock absorber, in combination, a casing, a rock-shaft extended into the casing, a piston secured to the rock-shaft, a partition member extending around the rock-shaft and piston, fluid-containing chambers on opposite sides of the piston, a by-pass between said chambers comprising a groove formed in said partition, a second groove formed in the piston and having tapering portions for automatically restricting the flow of fluid through the by-pass, as the travel of the piston is extended under abnormal road conditions, and a plunger member adjustably mounted in the partition and accessible from without the casing adapted to extend into the groove in the casing for restricting the fluid movement through the by-pass.

3. In a shock absorber, in combination, a casing provided with fluid-containing chambers, a piston in said casing, means for reciprocating said piston, a by-pass connecting said chambers and through which fluid may be forced freely in opposite directions by movement of said piston in opposite directions under normal road conditions, said by-pass having tapering portions for automatically restricting the iiow of fluid through said bypass as the travel of said piston is extended under abnormal road conditions, and a device co-operating with said by-pass between the tapering portions of the latter to regulate the quantity of fluid flowing in opposite directions through said by-pass, said device being accessible from outside the casing.

In testimony whereof, I have signed my name to this specilication.

FREDERICK O. KILGORE. 

